Author Notes:Bitters are an ingredient you can apply much more widely than you probably realize, because they won't beach themselves on top of everything else. They wriggle in and help existing flavors bloom, much like a subtle jolt of salt or acid or heat can. If you want to know if this riff really makes a difference, taste a little cup before and after adding the bitters. The drink will become fuller-flavored and more inviting, but in a hard to pin down way. Though the "before" cup will be good, it will likely taste two-dimensional by comparison. Adapted slightly from Modern Potluck (Random House, 2016). —Genius Recipes

In a blender or food processor, purée the watermelon. Strain the juice through a sieve into a pitcher. Add the lime juice, sugar, and bitters and stir with a long-handled spoon until the sugar is dissolved. Refrigerate for at least 1 hour.

Add the club soda, ice cubes, and sliced lime to the agua fresca and serve.

Notes: The agua fresca base can be refrigerated for up to 2 days. Add the club soda, ice cubes and sliced lime just before serving. For a large party, the recipe scales up well, and you can serve this in a punch bowl or wide-mouthed canister with a ladle.